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Inquiry LabDATASHEET FOR CHAPTER LAB

Roly-Poly Races

Have you ever watched a bug run? Did you wonder why it was running? The bug you saw running was probably reacting to a stimulus. In other words, something happened to make the bug run! One characteristic of living things is that they respond to stimuli. In this activity, you will study the movement of roly-polies. Roly-polies are also called pill bugs. But they are not really bugs; they are land-dwelling animals called isopods. Isopods live in dark, moist areas under rocks or wood. You will provide stimuli to determine how fast your isopod can move and what affects its speed and direction. Remember that isopods are living things and must be treated gently and respectfully.

objectives

Observe responses to stimuli.

Analyze responses to stimuli.

materials

•chalk (1 stick)

•container, plastic, small, with lid

•gloves, protective

•isopod (4)

Safety Information

Using Scientific Methods

Ask a Question

1.Ask a question such as, “Which stimuli cause pill bugs to run?”

Form a Hypothesis

2.Using your question as a guide, form a hypothesis. For example, you could form the following hypothesis: “Light, sound, and touch stimulate pill bugs to run.”

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Roly-Poly Races continued

Test the Hypothesis

3.Choose a partner, and decide together how you will run your roly-poly race. Discuss some gentle ways to stimulate your isopods to move. Choose five or six things that might cause movement, such as a gentle nudge or a change in temperature, sound, or light. Check your choices with your teacher.

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4.In the table below, label the columns with the stimuli that you’ve chosen.

Isopod Responses
Stimulus 1 / Stimulus 2 / Stimulus 3
Isopod 1
Isopod 2
Isopod 3
Isopod 4

5.Place a layer of soil that is 1 cm or 2 cm deep in a small plastic container. Add a small slice of potato and a piece of chalk. Your isopods will eat these items.

6.Place four isopods in your container. Observe them for a minute or two before you perform your tests. Record your observations.

7.Decide which stimulus you want to test first. Carefully arrange the isopods at the “starting line.” The starting line can be an imaginary line at one end of the container.

8.Gently stimulate each isopod at the same time and in the same way. In your data table, record the isopods’ responses to the stimulus. Be sure to record the distance that each isopod travels. Don’t forget to time the race.

9.Repeat steps 7–8 for each stimulus. Be sure to wait at least 2 minutes between trials.

Analyze the Results

1.Describing Events Describe the way that isopods move. Do their legs move together?

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Roly-Poly Races continued

2.Analyzing Results Did your isopods move before or between the trials? Did the movement seem to have a purpose, or were the isopods responding to a stimulus? Explain.

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Draw Conclusions

3.Interpreting Information Did any of the stimuli make the isopods move faster or go farther? Explain.

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Applying your data

Like isopods and all other living things, humans react to stimuli. Describe three stimuli that might cause humans to run.

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Original content Copyright © by Holt, Rinehart and Winston. Additions and changes to the original content are the responsibility of the instructor.

Holt Science and Technology1It’s Alive!! Or Is It?

Teacher Resources

Inquiry LabDATASHEET FOR CHAPTER LAB

Roly-Poly Races

Teacher Notes

Time Required

One or two 45-minute class periods

Lab Ratings

Teacher Prep–2

Student Set-Up–2

Concept Level–1

Clean Up–1

MATERIALS

The materials listed on the student page are enough for 1 or 2 students. Remind students that they are handling living things that should be treated with respect. The soil used in this lab should be sterilized potting soil to avoid causing allergic reactions among the students.

Safety Caution

Remind students to review all safety cautions and icons before beginning this lab activity.

Lab Notes

Isopods were selected for this lab because they are very common in most areas and can be collected and released in natural areas. If you choose to use other animals that you can obtain at a pet store, such as mealworms, be sure to have a plan for appropriate disposal after the lab.

Disposal Information

When the lab has been completed, the isopods can be disposed of according to your policy or can be released into a natural area if the isopods are native to that area.

Original content Copyright © by Holt, Rinehart and Winston. Additions and changes to the original content are the responsibility of the instructor.

Holt Science and Technology1It’s Alive!! Or Is It?